anteroseptal

adjective

an·​tero·​sep·​tal ˌan-tə-(ˌ)rō-ˈsep-tᵊl 

: located in front of a septum and especially the interventricular septum

An electrocardiogram showed atrial fibrillation, with a ventricular rate of 116 beats per minute, and confirmed the presence of an old anteroseptal infarct.

—Ursula B. Kaiser and E. Tessa Hedley-Whyte, The New England Journal of Medicine